In the Pacific Ocean the Tsunami Warning System (ITSU) has been set up to provide Pacific basin countries with surveillance and monitoring of tsunamigenic earthquakes, and for providing warnings to member countries when tsunamis are expected to be generated. The Pacific Tsunami Warning Center (PTWC) in Hawaii has overall responsibility for issuing tsunami advices and warnings to ITSU members. It is operated by the National Weather Service (NWS) of the USA. It advises appropriate authorities of the occurrence of an earthquake, and indicates whether or not a tsunami has been confirmed and provides estimates of travel time across the Pacific. It is not however in a position to predict actual run-up heights for the eventual landfall of a tsunami in Australia, as this depends on the complexities of coastal geography and offshore bathymetry.

International arrangements for tsunami warnings in the Indian Ocean are currently being developed.

In Australia, the Bureau of Meteorology has responsibility for issuing tsunami warnings. For areas covered by the PTWC the warnings are issued by the Bureau under guidance from the PTWC. At the present time the Australian Tsunami Alert System (ATAS) has been established by the Bureau of Meteorology, Geoscience Australia (GA) and Emergency Management Australia (EMA).

The ATAS provides tsunami warning services to all Australian coasts. GA provides the seismological expertise (earthquake detection and analysis). The National Tidal Centre of the Bureau of Meteorology provides sea-level monitoring expertise (tsunami detection). EMA provides expertise in community education, human communication and disaster management liaison. The Bureau of Meteorology provides communications, scientific support and warning provision/dissemination.

 Tsunamis act very differently from typical surf swells; they spread at high speeds and can travel great transoceanic distances with little energy loss. A tsunami can cause damage thousands of miles from its origin, so there may be several hours between its creation and its collision on the coast, more time than it takes for seismic waves to arrive.

Tsunamis have extremely long periods, 2 minutes to over one hour, and long wavelengths, in excess of 100 km. (Compare a typical wind-generated swell one sees at a surf beach, which might be spawned by a faraway storm and rhythmically roll in, one wave after another, with a period of about 10 seconds and a wavelength of 150 m.)

Typically undersea earthquakes give rise to between 3 and 5 distinct waves (crests), the second or third of which are usually the largest.

In instances where the leading edge of the tsunami is its trough, the sea will recede from the coast half the wave’s period before the wave’s arrival. If the slope is shallow, this recession can exceed 800 m. People unaware of the danger may remain at the shore due to curiosity, or for collecting fish from the dry sea bottom.

In instances where the leading edge of the tsunami is its first peak, low-lying coastal areas are flooded before the higher second wave reaches them. Again, being educated about a tsunami is significant, to realize that when the water level drops the first time, the danger is not yet over.

A wave becomes a shallow-water wave when the ratio between the water depth and its wavelength gets very small. Since a tsunami has a large wavelength, tsunamis act as a shallow-water wave even in deep oceanic water. Shallow-water waves move at a speed that is equal to the square root of the product of the acceleration of gravity (9.8 m/s2) and the water depth. For example, in the Pacific Ocean, where the typical water depth is about 4000 m, a tsunami travels at about 200 m/s (about 712 km/hr or 442 mi/hr) with little energy loss even for far distances, while at a water depth of 40 m, the speed is 20 m/s (about 71 km/hr or 44 mi/hr), much slower, but still difficult to outrun.

In deep water, the energy of a tsunami is constant, a function of its height and speed. Thus, as the wave approaches land, its height increases while its speed decreases. While in deep water a person at the surface of the water would probably not even notice the tsunami, the wave can increase to a height of 30 m and more as it approaches the coastline and compresses. Tsunamis can cause harsh destruction on coasts and islands, even at locations remote to the source event, where that event itself is not even noticable without instruments.

Tsunamis propagate outward from their source, so coasts in the “shadow” of affected land masses are regularly fairly safe. However, tsunami waves can diffract around land masses (as shown in this Indian Ocean tsunami animation as the waves reach southern Sri Lanka and India). They also need not be symmetrical; tsunami waves may be much stronger in one direction than another, depending on the nature of the source and the surrounding geography.

As a tsunami leaves the deep water of the open-ocean and actions into the shallower water near the shore, it transforms. The tsunami‘s power flux, which is dependent on both its wave force and wave altitude, remains nearly steady. Consequently, as the tsunami’s speed diminishes, its height grows. This is known as shoaling. Because of this shoaling effect, a tsunami that is invisible at sea, may grow to be quite a few metres or more in height near the coast.

The increase of the tsunami’s waveheight as it enters shallow water is given by: shallow height

Where hs and hd are waveheights in low and deep water and Hs and Hd are the depths of the low and deep water. So a tsunami with a height of 1 m in the open sea where the water depth is 4000m would have a waveheight of 4 to 5 m in water of deepness 10 m.

Just like additional water waves, tsunamis begin to lose energy as they rush onto land - part of the wave energy is reflect offshore, while the shoreward-propagating wave energy is dissolute through bottom resistance and turbulence. Despite these losses, tsunamis still reach the coast with marvelous amounts of energy. Depending on whether the first part of the tsunami to reach the shore is a crest or a furrow, it may appear as a quickly rising or falling tide. Local bathymetry may also cause the tsunami to come into view as a series of breaking waves.

Tsunami have great erosion possible, stripping beaches of sand that may have taken years to build up and undermining trees and other coastal vegetation. Capable of inundate, or flooding, hundreds of metres inland past the typical high-water stage, the fast-moving water associated with the flood tsunami can crush homes and other coastal structures. Tsunamis may reach a highest vertical height onshore above sea level, often called a run-up height, of tens of metres.

On Jan. 27, 1700 – more than a few hours after the last big tremble on the Oregon coast, Japanese reserachers have found written reports of a tsunami that strike a coastal village about 300 miles northeast of Tokyo

’At midnight . . a tsunami strikes Kuwagasaki town. . Village members went to hills. Fires broke out and 20 houses were destroyed. In adding, 13 houses were reported to have been ruined by the tsunami. Because the tsunami and fire happen at the similar time, villagers were incapable to move anything, let alone furnishings or tools. . . . Also, for those who missing their houses, the officials in charge of the hills made an demand for timber’ to build impermanent shelters.

A record by the head of Miho village, almost 90 miles southwest of Tokyo, told of sea water running up in a above the ground tide. “The moving back water passed out very quickly, like a river. It came almost seven times before 10 a.m.In that day.. Lost its power gradually. . . Because the way the time came in was so strange, and was in fact unheard of, advised the village members to flee to Miho Shrine. . . It is said when the earthquakes occurs, incredible like large swell result, but there was no earthquake in either the town or nearby.”

Although the wealthy oral histories of coastal tribes don’t offer a precise date about the last earthquake, they suggest that a huge earthquake and tsunami occurred on a winter night.

Deborah Carver, a investigator from Kodiak, Alaska, said a few stories explain a huge earthquake in which elders tell the young they must run for high ground because of floodwaters that will follow. After spending a cold night in the hills, they found that all traces of their village and neighboring villages have been washed away.

A story from the Yurok citizens of Northern California describe paranormal beings called Earthquake and Thunder running up and down the coast producing the ground to shake, sink and be flooded by the ocean

There is facts that the Australian coast may have experienced large tsunami during the past few thousand years. This evidence is revealed through deposits of shell, coral and boulders which are well on top of sea level and several kilometers inland…. Tsunami are recorded in Australia about once every two years but most are small and present little threat to coastal communities.

The tsunami threat to Australia varies from relatively low for most of the coastline to moderate on the north west coast of Western Australia. This area is more vulnerable because of its proximity to Indonesia and other countries in the area which are prone to major earthquake and volcanic activity.

Several major tsunami have hit Australia’s north west coast with the largest, at Cape Leveque in 1977, reportedly produce a six metre wave height

Further south in the Onslow-Exmouth region in June 1994, tsunami waves travelled inland to a point four metres over sea level and washed 300 metres inland after appearing out of a calm sea. Both tsunami were generated by earthquakes in Indonesia.

In May 1960, a scale 9.5 earthquake in Chile generated the largest tsunami recorded along the east coast of Australia. The event generated tsunami waves of just under one metre at the Fort Denison tide gauge in Sydney Harbour. Slight to reasonable damage was caused to boats in harbours at Lord Howe Island, Evans Head, Newcastle, Sydney and Eden.

Following the Indian Ocean tsunami on 26 December 20

04, the Australian Government committed funding of $68.9 million over four years in the 2005-2006 Federal Budget to upgrade the Australian Tsunami Alert System (ATAS) to an operational, early warning system - the Australian Tsunami Warning System (ATWS). The ATWS project is jointly managed by Geoscience Australia, the Bureau of Meteorology and Attorney-General’s Department, as represented by Emergency Management Australia (EMA).

The Australian Government’s funding is being utilised to:

* Establish the Joint Australian Tsunami Warning Centre with 24/7 monitoring and analysis capacity for the nation.

* Upgrade and expand sea-level and seismic monitoring networks around Australia.

* Implement national tsunami education and training programs.

* Assist the intergovernmental Oceanographic Commission to develop the existing Pacific Tsunami Warning System and establish the Indian Ocean Tsunami Warning System.

* Provide technical assistance to help build the capacity of scientists, technicians, and emergency managers in the South West Pacific and Indian Oceans.

EMA is mandated to build capacity and raise community awareness within relevant industry, education, volunteer and community sectors through education programs, activities and training. EMA has undertaken significant consultation and research to review and examine current practice, identify potential gaps or areas for improvement, and is developing and implementing a suite of public awareness and capacity development programs/activities relating to tsunami throughout the Australian States and Territories.

Significant progress has been made towards the implementation of various elements of this mandate including:

* Development of a suite of four tsunami awareness brochures

, including information for recreational marine users and recreational boaters.

* Development of an educational interactive CD Rom on tsunami for Surf Life Saving Australia employees and volunteers.

* Development and delivery of a series of in-service tsunami education workshops and presentations for emergency managers have been conducted throughout Australian States and Territories.

* Development of a suite of tsunami educational tools and programs aimed at culturally and linguistically diverse communities and indigenous communities.

* Tsunami community resilience research.

* A partnership with Questacon, the National Science and Technology Centre in Canberra, which includes the implementation of a Tsunami Awareness Show for children andthe general public, the production of an associated Tsunami Awareness Presentation DVD, production of an interactive tsunami education kiosk and development of a suite of children’s tsunami education activity sheets.

* Partnering with Australian States and Territories to provide tsumani awareness and capacity building activities throughout Australia.

The explosion of a volcano in the Canary Islands could trigger a ”mega-tsunami” that would demolish Atlantic coastlines with waves as far above the ground as 330 feet

They said an explosion of the Cumbre Vieja volcano on La Palma, it’s a part of the Spanish island chain off West Africa, was likely to damage a massive chunk of rock to break off, crashing into the sea and kicks up vast walls of water higher than any other in recorded history.

Tsunami would be ability of traveling huge distances at up to 500 miles an hour .. But Cumbre Vieja should be monitored directly for any signs of activity so that emergency services could plan an effective response…

Although the year-to-year chance of a collapse is therefore low, the resultant tsunami would be a major disaster with indirect effects around the world.

west sahara to bear brunt

The energy released by the collapse would be equivalent to the electricity consumption of the entire United States in half a year.

Immediately after the mud slide, a dome of water 900 meters (3,000 feet high) and tens of miles wide would form, only to collapse and bounce back.

The landslide ruins moved deeper under water, a tsunami would develop. Within 10 minutes, the tsunami would have moved a distance of about 155 miles.

On the west Saharan shore, waves would almost certainly reach heights of 330 feet.

Florida and the Caribbean the final north Atlantic destination to be affected by the tsunami would have to support themselves for 165 foot waves some eight to nine hours after the landslide.

Wave heights in the direction of Europe would be smaller, but substantial waves would hit the coasts of Britain, Spain, Portugal and France.

The research paper predictable water would penetrate several miles inland and that the devastation would cause trillions of dollars in damage.

Panel 1—Initiation:

Earthquakes are commonly associated with ground shaking that is a result of elastic-waves traveling through the solid earth. However, near the source of submarine earthquakes, the seafloor is “permanently“ uplifted and down-dropped, pushing the entire water column up and down. The potential energy that results from pushing water above mean sea level is then transferred to horizontal propagation of the tsunami wave kinetic-energy. For the case shown above, the earthquake rupture occurred at the base of the continental slope in relatively deep water. Situations can also arise where the earthquake rupture occurs beneath the continental shelf in much shallower water.

Panel 2-Split:

Within several minutes of the earthquake, the initial tsunami (Panel 1) is split into a tsunami that travels out to the deep ocean (distant tsunami) and another tsunami that travels towards the nearby coast (local tsunami). The height above mean sea level of the two oppositely traveling tsunamis is approximately half that of the original tsunami (Panel 1). (This is somewhat modified in three dimensions, but the same idea holds.) The speed at which both tsunamis travel varies as the square root of the water depth. Therefore, the deep-ocean tsunami travels faster than the local tsunami near shore

Panel 3-Amplification

Several things happen as the local tsunami travelsover the continental slope. Most obvious is that the amplitude increases. In addition, the wavelength decreases. This results in steepening of the leading wave–an important control of wave runup at the coast (next panel). Note that the first part of the wave reaching the local shore is a trough, which will appear as the sea receeding far from shore. This is a common natural warning sign for tsunamis. Note also that the deep ocean tsunami has traveled much farther than the local tsunami because of the higher propagation speed. As the deep ocean tsunami approaches a distant shore, amplification and shortening of the wave will occur, just as with the local tsunami shown above.

Panel 4-Runup:

Tsunami runup occurs when a peak in the tsunami wave travels from the near-shore region onto shore. Runup is a measurement of the height of the water onshore observed above a reference sea level. Except for the largest tsunamis, such as the 2004 Indian Ocean event, most tsunamis do not result in giant breaking waves (like normal surf waves at the beach that curl over as they approach shore). Rather, they come in much like very strong and fast-moving tides (i.e., strong surges and rapid changes in sea level). Much of the damage inflicted by tsunamis is caused by strong currents and floating debris. The small number of tsunamis that do break often form vertical walls of turbulent water called bores. Tsunamis will often travel much farther inland than normal waves.

Tsunamis can have wavelengths ranging from 10 to 500 km and wave periods of up to an hour. As a result of their long wavelengths, tsunamis act as shallow-water waves. A wave becomes a shallow-water wave when the wavelength is very large compared to the water depth. Shallow-water waves move at a speed, c, that is dependent upon the water depth and is given by the formula: phase speed where g is the acceleration due to gravity (= 9.8 m/s2) and H is the depth of water. In the deep ocean, the typical water depth is around 4000 m, so a tsunami will therefore travel at around 200 m/s, or more than 700 km/hr. For tsunamis that are generated by underwater earthquakes, the amplitude (i.e.wave height) of the tsunami is determined by the amount by which the sea-floor is displaced. Similarly, the wavelength and period of the tsunami are determined by the size and shape of the underwater disturbance. As well as travelling at high speeds, tsunamis can also travel large distances with limited energy losses. As the tsunami propagates across the ocean, the wave crests can undergo refraction (bending), which is caused by segments of the wave moving at different speeds as the water depth along the wave crest varies.